https://imgur.com/a/mH2earq
^ Here's a crappy diagram of the setup.
It's self made and wasn't the best idea I had.
The brown coloured bit is an open topped formicarium where I was hoping they would dig.
The yellow/ orange is the outworld area.
The black dot is the entrance.
It is a very small, one queen myrmica rubra colony (probably 15 workers but I don't know since they all hide underground. It was about 10 when they moved in 2 weeks ago)
They dug where I was hoping they would but I have made their formicarium thing too wide (2.5 cm) and I can't see their tunnels. I have purchased an antkit medium size 4 nest series 3 (https://antkit.uk/collections/nests/products/antkit-acrylic-nest-series-3-size-4-medium) for them to move into and placed it in their outworld bit, hoping they would move in but they have a moist formicarium nest thing (This i cannot change as it will stay moist and it's difficult to explain) and have no reason for them to move out but I really want to be able to check on them to see how they are doing. How do you think i can get them to move out? Please no comments telling me to leave them, it's not what I'm looking for

https://imgur.com/a/mH2earq
^ Here's a crappy diagram of the setup.
It's self made and wasn't the best idea I had.
The brown coloured bit is an open topped formicarium where I was hoping they would dig.
The yellow/ orange is the outworld area.
The black dot is the entrance.
It is a very small, one queen myrmica rubra colony (probably 15 workers but I don't know since they all hide underground. It was about 10 when they moved in 2 weeks ago)
They dug where I was hoping they would but I have made their formicarium thing too wide (2.5 cm) and I can't see their tunnels. I have purchased an antkit medium size 4 nest series 3 (https://antkit.uk/collections/nests/products/antkit-acrylic-nest-series-3-size-4-medium) for them to move into and placed it in their outworld bit, hoping they would move in but they have a moist formicarium nest thing (This i cannot change as it will stay moist and it's difficult to explain) and have no reason for them to move out but I really want to be able to check on them to see how they are doing. How do you think i can get them to move out? Please no comments telling me to leave them, it's not what I'm looking for

The best method usually is to put light and heat directly on the nest, but considering you can't see the tunnels, you could mix lemon juice and water and squirt it into the nest. I believe, according to other forum members, that the lemon's acidity makes the nest unsuitable for the ants to live in, so the ants move out. So your new nest is probably the most suitable nesting spot available, so they'll most likely move into the new nest.

"God made every kind of wild beasts and every kind of livestock and every kind of creeping things;" (including ants) "and God saw that it was good." Genesis 1:25

I think, as indicated by other discussion individuals, that the lemon's causticity makes the home inadmissible for the ants to live in, so the ants move out, so your new home is likely the most appropriate settling spot accessible...

It is better to be hated for what you are than to be loved for what you are not

Make sure to keep your new nest in the dark while exposing the current one to light and heat. You can also make the new nest moist and the old one more dry. Just give the ants some time and they will relocate to the new nest eventually. Sometimes this takes days, but most of the time they will relocate the colony in a few hours. Hope this helps!